First crack at a Prime Number Sieve in Ruby...

prime_sieve.rb

class PrimeSieve

def for(range)
    sieve = Array(range)
    sieve.delete 1

    sieve.each do |i|
        sieve.each do |j|
            if(i != j && j%i == 0)
                sieve.delete(j)
            end
        end
    end

end

end

prime_sieve_spec.rb

load 'prime_sieve.rb'

describe PrimeSieve  do


it "returns 2 for (1..2)" do
        range = (1..2)
        prime_sieve = PrimeSieve.new
        prime_sieve.for(range).should == [2]
    end
it "returns [2,3] for (1..4)" do
    range = (1..4)
    prime_sieve = PrimeSieve.new
    prime_sieve.for(range).should == [2,3]
    end


it "returns [2,3,5] for (1..5)" do
    range = (1..5)
    prime_sieve = PrimeSieve.new
    prime_sieve.for(range).should == [2,3,5]
    end

it "return [2,3,5,7,11,13] for (1..14)" do
    range = (1..14)
    prime_sieve = PrimeSieve.new
    prime_sieve.for(range).should == [2,3,5,7,11,13]
    end

it "returns [2,3,5,7,11,13,17,19] for (1..20)" do
    range = (1..20)
    prime_sieve = PrimeSieve.new
    prime_sieve.for(range).should == [2,3,5,7,11,13,17,19]
    end

end